Dual-Stack AO2 Client to handle both TCP and Websocket connections seemlessly (#696)

* Replace TCP Serversocket with Websocket

* Have TCP sockets live harmoniously with WS

"like 5 lines" yeah probably lost a bet.

* Update .gitlab-ci.yml

* hack to fix favorites

* Add support for websockets in the favorites list (serverlist.txt)
Make "add_favorite_server" remember the socket type

* Preserve old serverlist style

This will keep new entries compatible with 2.9 and prior clients. Makes parsing the list easier too.

* Add lookup table and correct write code to use lowercase

* I have no idea what a lookup table is, but this looks close enough

* Fix lookup table

* Otherwise backend selection behaviour is inverted

* clang-tidy had one job

* Yet it did not do it.

Co-authored-by: oldmud0 <oldmud0@users.noreply.github.com>

* const p_data

* Switch serverlist.txt to an ini format

* Fixes an Omni bug where : would split the servername
* Utilises internally QSettings properly for low parsing effort and clear structure
* Automatically migrates the legacy serverlist.txt to favorite_servers.ini
* Pleases my OCD

* Replace sample serverlist.

Co-authored-by: oldmud0 <oldmud0@users.noreply.github.com>
Co-authored-by: stonedDiscord <Tukz@gmx.de>
Co-authored-by: Alex Noir <Varsash@gmail.com>

3 files changed, 161 insertions, 60 deletions

diff --git a/src/aoapplication.cpp b/src/aoapplication.cpp
index 13c995f2..1e70ca93 100644
--- a/src/aoapplication.cpp
+++ b/src/aoapplication.cpp
@@ -144,12 +144,22 @@ void AOApplication::add_favorite_server(int p_server)
     return;
 
   server_type fav_server = server_list.at(p_server);
+  QSettings l_favorite_ini(get_base_path() + "favorite_servers.ini", QSettings::IniFormat);
+  QString l_new_group = QString::number(l_favorite_ini.childGroups().size());
+  l_favorite_ini.setIniCodec("UTF-8");
 
-  QString str_port = QString::number(fav_server.port);
+  l_favorite_ini.beginGroup(l_new_group);
+  l_favorite_ini.setValue("name", fav_server.name);
+  l_favorite_ini.setValue("address", fav_server.ip);
+  l_favorite_ini.setValue("port", fav_server.port);
 
-  QString server_line = fav_server.ip + ":" + str_port + ":" + fav_server.name;
-
-  write_to_serverlist_txt(server_line);
+  if (fav_server.socket_type == TCP) {
+   l_favorite_ini.setValue("protocol", "tcp");
+  }
+  else {
+    l_favorite_ini.setValue("protocol", "ws");
+  }
+  l_favorite_ini.sync();
 }
 
 void AOApplication::server_disconnected()
diff --git a/src/networkmanager.cpp b/src/networkmanager.cpp
index 4c823852..8f419fce 100644
--- a/src/networkmanager.cpp
+++ b/src/networkmanager.cpp
@@ -4,6 +4,7 @@
 #include "debug_functions.h"
 #include "lobby.h"
 
+#include <QAbstractSocket>
 #include <QJsonArray>
 #include <QJsonDocument>
 #include <QNetworkReply>
@@ -12,15 +13,9 @@ NetworkManager::NetworkManager(AOApplication *parent) : QObject(parent)
 {
   ao_app = parent;
 
-  server_socket = new QTcpSocket(this);
   http = new QNetworkAccessManager(this);
   heartbeat_timer = new QTimer(this);
 
-  connect(server_socket, &QTcpSocket::readyRead, this,
-          &NetworkManager::handle_server_packet);
-  connect(server_socket, &QTcpSocket::disconnected, ao_app,
-          &AOApplication::server_disconnected);
-
   QString master_config =
       ao_app->configini->value("master", "").value<QString>();
   if (!master_config.isEmpty() && QUrl(master_config).scheme().startsWith("http")) {
@@ -60,10 +55,18 @@ void NetworkManager::ms_request_finished(QNetworkReply *reply,
     const auto entry = entryRef.toObject();
     server_type server;
     server.ip = entry["ip"].toString();
-    server.port = entry["port"].toInt();
     server.name = entry["name"].toString();
     server.desc = entry["description"].toString(tr("No description provided."));
-    server_list.append(server);
+    if (entry["ws_port"].isDouble()) {
+      server.socket_type = WEBSOCKETS;
+      server.port = entry["ws_port"].toInt();
+    } else {
+      server.socket_type = TCP;
+      server.port = entry["port"].toInt();
+    }
+    if (server.port != 0) {
+        server_list.append(server);
+    }
   }
   ao_app->set_server_list(server_list);
 
@@ -128,26 +131,99 @@ void NetworkManager::request_document(MSDocumentType document_type,
 
 void NetworkManager::connect_to_server(server_type p_server)
 {
-  server_socket->close();
-  server_socket->abort();
+  disconnect_from_server();
 
   qInfo().nospace().noquote() << "connecting to " << p_server.ip << ":"
                               << p_server.port;
 
-  server_socket->connectToHost(p_server.ip, p_server.port);
+  switch (p_server.socket_type) {
+  default:
+    p_server.socket_type = TCP;
+    [[fallthrough]];
+  case TCP:
+    qInfo() << "using TCP backend";
+    server_socket.tcp = new QTcpSocket(this);
+
+    connect(server_socket.tcp, &QAbstractSocket::connected, this, [] {
+      qDebug() << "established connection to server";
+    });
+    connect(server_socket.tcp, &QIODevice::readyRead, this, [this] {
+      handle_server_packet(QString::fromUtf8(server_socket.tcp->readAll()));
+    });
+    connect(server_socket.tcp, &QAbstractSocket::disconnected, ao_app,
+            &AOApplication::server_disconnected);
+    connect(server_socket.tcp, &QAbstractSocket::errorOccurred, this, [this] {
+      qCritical() << "TCP socket error:" << server_socket.tcp->errorString();
+    });
+
+    server_socket.tcp->connectToHost(p_server.ip, p_server.port);
+    break;
+  case WEBSOCKETS:
+    qInfo() << "using WebSockets backend";
+    server_socket.ws = new QWebSocket(QString(), QWebSocketProtocol::VersionLatest, this);
+
+    connect(server_socket.ws, &QWebSocket::connected, this, [] {
+      qDebug() << "established connection to server";
+    });
+    connect(server_socket.ws, &QWebSocket::textMessageReceived, this,
+            &NetworkManager::handle_server_packet);
+    connect(server_socket.ws, &QWebSocket::disconnected, ao_app,
+            &AOApplication::server_disconnected);
+    connect(server_socket.ws, QOverload<QAbstractSocket::SocketError>::of(&QWebSocket::error),
+            this, [this] {
+      qCritical() << "WebSockets error:" << server_socket.ws->errorString();
+    });
+
+    QUrl url;
+    url.setScheme("ws");
+    url.setHost(p_server.ip);
+    url.setPort(p_server.port);
+    QNetworkRequest req(url);
+    req.setHeader(QNetworkRequest::UserAgentHeader, get_user_agent());
+    server_socket.ws->open(req);
+    break;
+  }
+
+  connected = true;
+  active_connection_type = p_server.socket_type;
+}
+
+void NetworkManager::disconnect_from_server()
+{
+  if (!connected)
+    return;
+
+  switch (active_connection_type) {
+  case TCP:
+    server_socket.tcp->close();
+    server_socket.tcp->deleteLater();
+    break;
+  case WEBSOCKETS:
+    server_socket.ws->close(QWebSocketProtocol::CloseCodeGoingAway);
+    server_socket.ws->deleteLater();
+    break;
+  }
+
+  connected = false;
 }
 
 void NetworkManager::ship_server_packet(QString p_packet)
 {
-  server_socket->write(p_packet.toUtf8());
+  switch (active_connection_type) {
+  case TCP:
+    server_socket.tcp->write(p_packet.toUtf8());
+    break;
+  case WEBSOCKETS:
+    server_socket.ws->sendTextMessage(p_packet);
+    break;
+  }
 }
 
-void NetworkManager::handle_server_packet()
+void NetworkManager::handle_server_packet(const QString& p_data)
 {
-  QByteArray buffer = server_socket->readAll();
-  QString in_data = QString::fromUtf8(buffer, buffer.size());
+  QString in_data = p_data;
 
-  if (!in_data.endsWith("%")) {
+  if (!p_data.endsWith("%")) {
     partial_packet = true;
     temp_packet += in_data;
     return;
diff --git a/src/text_file_functions.cpp b/src/text_file_functions.cpp
index b5bd6968..0dde68f6 100644
--- a/src/text_file_functions.cpp
+++ b/src/text_file_functions.cpp
@@ -236,52 +236,30 @@ bool AOApplication::append_to_file(QString p_text, QString p_file,
   return false;
 }
 
-void AOApplication::write_to_serverlist_txt(QString p_line)
-{
-  QFile serverlist_txt;
-  QString serverlist_txt_path = get_base_path() + "serverlist.txt";
-
-  serverlist_txt.setFileName(serverlist_txt_path);
-
-  if (!serverlist_txt.open(QIODevice::WriteOnly | QIODevice::Append)) {
-    return;
-  }
-
-  QTextStream out(&serverlist_txt);
-  out.setCodec("UTF-8");
-  out << "\r\n" << p_line;
-
-  serverlist_txt.close();
-}
-
 QVector<server_type> AOApplication::read_serverlist_txt()
 {
   QVector<server_type> f_server_list;
 
-  QFile serverlist_txt;
-  QString serverlist_txt_path = get_base_path() + "serverlist.txt";
-
-  serverlist_txt.setFileName(serverlist_txt_path);
-
-  if (serverlist_txt.open(QIODevice::ReadOnly)) {
-      QTextStream in(&serverlist_txt);
-      in.setCodec("UTF-8");
+  QFile serverlist_txt(get_base_path() + "serverlist.txt");
+  QFile serverlist_ini(get_base_path() + "favorite_servers.ini");
 
-      while (!in.atEnd()) {
-        QString line = in.readLine();
-        server_type f_server;
-        QStringList line_contents = line.split(":");
-
-        if (line_contents.size() < 3)
-          continue;
-
-        f_server.ip = line_contents.at(0);
-        f_server.port = line_contents.at(1).toInt();
-        f_server.name = line_contents.at(2);
-        f_server.desc = "";
+  if (serverlist_txt.exists() && !serverlist_ini.exists()) {
+    migrate_serverlist_txt(serverlist_txt);
+  }
 
-        f_server_list.append(f_server);
-      }
+  if (serverlist_ini.exists()) {
+    QSettings l_favorite_ini(get_base_path() + "favorite_servers.ini", QSettings::IniFormat);
+    l_favorite_ini.setIniCodec("UTF-8");
+    for(QString &fav_index: l_favorite_ini.childGroups()) {
+      server_type f_server;
+      l_favorite_ini.beginGroup(fav_index);
+      f_server.ip = l_favorite_ini.value("address", "127.0.0.1").toString();
+      f_server.port = l_favorite_ini.value("port", 27016).toInt();
+      f_server.name = l_favorite_ini.value("name", "Missing Name").toString();
+      f_server.socket_type = to_connection_type.value(l_favorite_ini.value("protocol", "tcp").toString());
+      f_server_list.append(f_server);
+      l_favorite_ini.endGroup();
+    }
   }
 
   server_type demo_server;
@@ -294,6 +272,43 @@ QVector<server_type> AOApplication::read_serverlist_txt()
   return f_server_list;
 }
 
+void AOApplication::migrate_serverlist_txt(QFile &p_serverlist_txt)
+{
+  // We migrate our legacy serverlist.txt to a QSettings object.
+  // Then we write it to disk.
+  QSettings l_settings(get_base_path() + "favorite_servers.ini", QSettings::IniFormat);
+  l_settings.setIniCodec("UTF-8");
+  if (p_serverlist_txt.open(QIODevice::ReadOnly)) {
+    QTextStream l_favorite_textstream(&p_serverlist_txt);
+    l_favorite_textstream.setCodec("UTF-8");
+    int l_entry_index = 0;
+
+    while (!l_favorite_textstream.atEnd()) {
+      QString l_favorite_line = l_favorite_textstream.readLine();
+      QStringList l_line_contents = l_favorite_line.split(":");
+
+      if (l_line_contents.size() >= 3) {
+        l_settings.beginGroup(QString::number(l_entry_index));
+        l_settings.setValue("name", l_line_contents.at(2));
+        l_settings.setValue("address", l_line_contents.at(0));
+        l_settings.setValue("port", l_line_contents.at(1));
+
+        if (l_line_contents.size() >= 4) {
+          l_settings.setValue("protocol", l_line_contents.at(3));
+        }
+        else {
+          l_settings.setValue("protocol","tcp");
+        }
+        l_settings.endGroup();
+        l_entry_index++;
+      }
+    }
+    l_settings.sync();
+  }
+  p_serverlist_txt.close();
+  p_serverlist_txt.rename(get_base_path() + "serverlist_depricated.txt");
+}
+
 QString AOApplication::read_design_ini(QString p_identifier,
                                        VPath p_design_path)
 {